Re: Infinite loop in parsing <()?

[Peter Stephenson <pws@csr.com>]

On Thu, 25 Mar 2010 12:17:48 +0100
Christian Neukirchen <chneukirchen@gmail.com> wrote:
> Bart Schaefer <schaefer@brasslantern.com> writes:
> 
> > On Mar 24,  7:22pm, Christian Neukirchen wrote:
> > }
> > } % cat <(echo foo | sort)
> > } # 100% CPU usage
> >
> > My guess would be that you have an alias for "sort" ...?
> 
> Whoops, right: 
> sort='LC_ALL=C sort'
> 
> % cat <(echo foo | LC_ALL=C sort)
> 
> works in zsh -f, but not with the alias set.

Yes, that's 100% reproducible.  Took a little hunting down.  This is a
local diff since CVS is a bit slow.

--- Src/input.c	2010-01-18 10:17:49.000000000 +0000
+++ ../zsh-debug/zsh/Src/input.c	2010-03-25 12:58:04.000000000 +0000
@@ -195,21 +195,24 @@
 	    return lastc;
 	}
 
-	/* If the next element down the input stack is a continuation of
-	 * this, use it.
-	 */ 
-	if (inbufflags & INP_CONT) {
-	    inpoptop();
-	    continue;
-	}
 	/*
-	 * Otherwise, see if we have reached the end of input
+	 * See if we have reached the end of input
 	 * (due to an error, or to reading from a single string).
+	 * Check the remaining characters left, since if there aren't
+	 * any we don't want to pop the stack---it'll mark any aliases
+	 * as not in use before we've finished processing.
 	 */
-	if (strin || errflag) {
+	if (!inbufct && (strin || errflag)) {
 	    lexstop = 1;
 	    return ' ';
 	}
+	/* If the next element down the input stack is a continuation of
+	 * this, use it.
+	 */
+	if (inbufflags & INP_CONT) {
+	    inpoptop();
+	    continue;
+	}
 	/* As a last resort, get some more input */
 	if (inputline())
 	    return ' ';
--- Test/A02alias.ztst	2009-03-03 17:08:12.000000000 +0000
+++ ../zsh-debug/zsh/Test/A02alias.ztst	2010-03-25 13:00:07.000000000 +0000
@@ -36,3 +36,9 @@
 >Without
 >This command has the argument true
 >With
+
+  print -u $ZTST_fd 'This test hangs the shell when it fails...'
+  alias sort='LC_ALL=C sort'
+  cat <(echo foo | sort)
+0:Alias expansion works at the end of parsed strings
+>foo

-- 
Peter Stephenson <pws@csr.com>            Software Engineer
Tel: +44 (0)1223 692070                   Cambridge Silicon Radio Limited
Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, UK


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